The present invention relates to a modular micro-chem lab. More specifically, the present invention relates to a hand-held micro-them lab which is preferably pre-fabricated onto a circuit board and which permits preconcentrators and/or sensors to be quickly and easily interchanged.
Note that the following discussion refers to a number of publications by author(s) and year of publication, and that due to recent publication dates certain publications are not to be considered as prior art vis-a-vis the present invention. Discussion of such publications herein is given for more complete background and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
Hand-held chemical testing devices employing preconcentrators have been known for sometime. In such devices, a gas or liquid is typically first passed over or through a preconcentrator, which typically comprises a heatable material that is selected based on that material's ability to sorb the chemical to be tested. Accordingly, the selectively sorbent material of the preconcentrator acquires an excess of the chemical to be tested. Upon rapid heating of the preconcentrator, the sorbed chemical is rapidly liberated. Because the preconcentrator is in fluid contact with the sensor, the rapid liberation of the chemical to be tested is seen as a chemical spike on the sensor. The magnitude of the spike is thus directly proportional to the quantity of gas emitted by the preconcentrator.
U.S. Pat. No. 6,772,513 to Frye-Mason et al. describes a chemical microanalytical system which has a preconcentrator and a chemical detector. U.S. Pat. No. 6,171,378 to Manginell et al. also describes a chemical preconcentrator for a hand-held chemical testing device. These and other known chemical sampling and testing devices, however, do not permit a user to rapidly replace the preconcentrator and/or sensor within a sealed environment. The preconcentrator of Frye-Mason et al. for example, provides a single preconcentrator die, which contains not only the selectively sorptive material and the heating element, but also a seal ring. Accordingly each preconcentrator die is further required to also contain a seal ring which must be manufactured and maintained after each use such that the seal ring is kept to exacting tolerances in order to prevent any leakages. Frye-Mason et al. further require that that the preconcentrator die be electrically and fluidically glued to the microfluidic substrate by the use of epoxies and/or solders (col. 4, lines 42-60), thus making rapid replacement of such dies impossible.
Because the aforementioned patents, and other known chemical testing devices do not permit the rapid replacement of the preconcentrator and/or sensor within a sealed environment, these and other known devices further require significant down-time when changing the sensor and preconcentrator so that a different chemical can be detected and measured. Still further, because these and other known devices are not designed to be rapidly re-tooled to detect different chemicals, the known testing devices also require a significant amount of re-wiring when changing from one sensor to the next. There is thus a need for a method and apparatus which permits a user to rapidly and effectively replace the preconcentrator and the sensor within a sealed environment and which further requires little or no re-wiring, soldering, or gluing when changing from one sensor and preconcentrator to the next.